feat(settings): add Skills and Memory pages

[rafavalls]

Summary

Two new org-settings surfaces under the Build group:

• Skills — lists the SKILL.md folders an agent can load on demand. A new skills settings group also adopts the existing Synced repos tab, since syncing skills from a repo is a skills concern rather than a storage one (it is how an org keeps the agent's skills current without hand-uploading each).
• Memory — what agents remember across tasks.

Testing

tsc --noEmit clean on apps/web. No behavior change to existing settings surfaces beyond Synced repos moving groups.

Notes for the reviewer

Memory ships as a labelled preview. Its entries are sample data and are not persisted yet; the UI says so via settings.memory.mockNotice. This is deliberate, so the surface can be reviewed before the persistence layer lands. If you'd rather not merge a preview surface, this PR is easy to hold or trim to Skills only.

Independent of the board/thread work in the sibling PRs; no shared files.

🤖 Generated with Claude Code

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Summary by cubic

Adds two new org Settings pages under Build: Skills (lists loadable SKILL.md folders) and Memory (what agents remember across tasks). Synced repos moves from Storage to the new Skills group. Previously: Synced repos lived under Storage; now: under Skills. No other existing settings behavior changes.

• New routes and nav: /$org/settings/skills and /$org/settings/memory; sidebar updated. /$org/settings/synced-repos stays the same path but is now keyed to the Skills group for loading state.
• Skills: fetches the org skill catalog and lists skills with “View in Library”; “Add” links to Library to create a SKILL.md.
• Memory: preview-only UI with sample data; entries are not persisted and the page shows a notice; remove acts on local state only.
• i18n: English and pt-BR strings added for Skills and Memory.

^{Written for commit 1bfe40f. Summary will update on new commits.}